1. Field of the Invention
The present invention relates to a high-current power source apparatus primarily used as the power source for a motor that drives an automobile such as a hybrid car or electric vehicle (EV), and in particular to a power source apparatus that prevents the ingress of water into the case that houses the batteries.
2. Description of the Related Art
An automobile such as an electric vehicle driven by a motor or a hybrid car driven by both a electric motor and an engine has a power source apparatus with a case housing batteries installed on-board. Since the vehicle is driven by an electric motor, the power source apparatus has many batteries connected in series to increase the voltage for large output. For example, although the voltage for a standard automobile electric system battery (lead-acid storage battery) installed in most cars is almost without exception 12V, the output voltage of a power source apparatus that powers a driving motor is extremely high and typically 200V or more.
The batteries in this type of power source apparatus can be protected by making the case that houses the batteries a water-tight structure. This is necessary because water ingress into the case can corrode the batteries and internal metal components. In addition, water ingress into the case can also be the cause of leakage currents and electrical shocks.
A car power source apparatus with a case made as a water-tight structure has been developed to avoid these detrimental effects. (Refer to Japanese Laid-Open Patent Publication 2006-35915.)
As shown in FIG. 1, the power source apparatus cited in JP 2006-35915-A has base-plate 94 open regions closed-off by a top cover 97 and an electronic component cover 98, and the boundaries with the top cover 97 and the electronic component cover 98 are made water-tight with gaskets 95. However, it is difficult to reliably sandwich the gaskets 95 for this water-tight structure, and it has the drawback that long-term maintenance of a reliable water-tight configuration at the top cover 97 and electronic component cover 98 boundaries is problematic. Further, although the boundaries of the top cover and the electronic component cover of this power source apparatus can be made in a water-tight configuration, the structure has connecting regions between the base-plate and the perimeter of the top cover, and it has both ends of the base-plate closed-off by side-plates. Consequently, this configuration has the drawback that connecting regions at the side-plates, the top cover, and the electronic component cover cannot be sealed in a satisfactory water-tight configuration.
The present invention was developed with the object of correcting the drawbacks described above. Thus, it is an important object of the present invention to provide a car power source apparatus that can make the case housing the battery blocks and battery state detection section water-tight with an extremely simple structure, and can effectively prevent water ingress into the case to effectively prevent corrosion and electrical shock.